Sealed crimp-type coaxial cable connection



Feb. 18, 1969 s. H.JAKSON SEALED CRIMP TYPE COAXIAL CABLE CONNECTION Filed Jan. 12, 1967 I/I/I/I/I/(i ///////l f IIIIIIIIIIIIIII .4

INVENTOR. JIM/[.4 Am flr/am/v United States Patent Office 3,428,739 Patented Feb. 18, 1969 6 Claims ABSTRACT OF THE DISCLOSURE A coaxial cable has an outer cylindrical sleeve having a uniform internal diameter, the sleeve having an elastomeric annulus in an internal recess. The outer face of the sleeve is compressed to distort the sleeve and is forced tightly against the outer conductor of the cable and to prevent entrance of moisture.

The present invention is directed to cable grips and more particularly to a character of mechanism which is especially adapted for coaxial cables and other like structures.

Such a mechanism of the prior art is shown in Patent No. 3,195,098, date July 13, 1965, in which there is described the gripping of a coaxial cable by a mechanism including a pair of sleeves. The inner sleeve is longitudinally slotted and the inner wire of the coaxial cable with the surrounding insulation is held therein. The end of the surrounding peripheral conductor lies on the inner sleeve and an outer sleeve placed over said end grips the peripheral conductor. While the functioning of the unit is satisfactory where it is not subject to moisture or water, it has the defect that it is not waterproof and water has entered under the sleeve from one or both ends, thus causing undesirable disturbances, such as short-circuiting, voltage breakdown and noise.

The present invention is intended and adapted to overcome the disadvantages inherent in prior art structures of the above described type, it being among the objects thereof to so modify the prior clamps as to render the structure proof against entrance of moisture or water.

It is also among the objects of the invention to provide a structure which is simple and not expensive, and which at the same time is hightly effective without adding expense in the fabrication thereof.

-It is further among the objects of the invention to devise a method of producing the gripping element which results in the formation of the aforesaid weatherproof joint or grip.

In practicing the invention the several elements of the complete structure, as shown in said patent, are utilized with the exception of the sleeve. Instead of the prior outer cylindrical sleeve having a uniform diameter both inside and outside, applicant provides a stepped sleeve or ferrule. Preferably, the wall thickness is uniform throughout but there are formed one or more annular steps. This provides at least one area within the sleeve which has an annular recess into which is fitted a corresponding annulus of a synthetic or other elastomeric material, such as natural or synthetic rubber, plastic or the like, which are readily deformable upon the application of suitable pressure. It is preferable that the annulus have resiliency.

The function thereof is to provide a resilient material which will readily be deformed and will fill all gaps be tween outer sleeve and cable jacket or inner sleeve. This helps overcome the wide tolerances encountered in cable manufacture. There is also provided a die which is angular internally and which clamps the sleeve onto the cable in such a manner as to exert pressure at one or more areas or points to distort the sleeve and annulus to cause the latter to more firmly grip the cable along said areas, and thus to prevent entrance of moisture.

The invention is more specifically described in conjunction with the accompanying drawing in which like reference characters indicate like parts and in which;

FIG. 1 is an exploded view of a portion of a coaxial cable connector showing the use of the sleeve or ferrule of the present invention in cross-section;

FIG. 2 is an end view of the sleeve looking from the right and showing the elastic annulus in place;

FIG. 3 is a front elevational view of a swaging tool or die for use in the making of the cable grip;

FIG. 4 is a transverse cross-sectional view of the crimped cable grip with the swaging tool still place;

FIGS. 5 and 6 are longitudinal cross-sectional views showing two modifications of the sleeve; and

FIG. 7 is a cross-sectional view of a unit made in accordance with the invention.

As shown in FIG. 1, the coaxial cable consists of a central conductor 1 covered by a dielectric material 2. This, in turn, is covered with a woven conducting sheath 3 and the unit is enclosed in a waterproofing insulating jacket 4. The sleeve or ferrule 5 consists of a cylindrical portion 6 at the center and having expanded or stepped portions 7 at one or both ends. A rubber or similar insert or annulus 8 is inserted in each of the expanded ends and the inner diameter 9 of portion 6 is approximately the same as the inner diameter of annulus 8.

As shown in FIG. 3, the swaging tool consists essentially of an upper die 11 having openings 12 for mounting on a suitable actuating device. At the lower edge 13 is an angular recess 14 having three sides. A complementary lower die 15 has openings 16 for mounting so that when the two dies meet along edge 13, angular recess 17 is complementary to recess 14 and together they form a hexagon. Other forms having different numbers of sides or being rounded or having sides of unequal lengths, may also be provided.

In the operation of the invention, the several elements 1-8 are assembled by slipping the cable to the right (FIG. 1) so that conductor 1 and its insulating jacket 2 enter into inner sleeve 18 which has longitudinal slots and inner recesses 20. The outer face of sleeve 18 is roughened as shown at 21. The woven conducting sheath 3 and its waterproof jacket 4 surround inner sleeve 18. The right hand end of sleeve 5 is placed over lower die 15, and upper die 11 is forced down until edges 13 of both dies meet. The result is shown in FIG. 4. The flat faces of both dies compress and distort ferrule 5, compressing annulus 8 along those areas and forcing the compressed portions tightly against the cable. The dotted lines 5' show the distorted areas of sleeve 5 and annulus 8. The die is simultaneously applied to the left hand end of ferrule or sleeve 5 to similarly distort certain areas thereof. The resiliency and compressibility of the elostomer will result in the annulus filling even the minutest gap between the sleeve and the cable in the assembly. It has been found that such a structure is completely tight against the entrance of moisture in any form.

The ferrule or sleeve may have other forms while performing the intended function. In FIG. 5 is shown a ferrule or sleeve 5 having a uniform inside diameter. At area 22 the sleeve is expanded to form at the lefthand end a recess 23 into which the elastomeric annulus 24 is inserted. The inner face 25 thereof has the same diameter as that of the sleeve. This end of the sleeve is spun over at 22' to enclose the end of annulus 24. At the opposite end 26 of sleeve 5, it is expanded to form recess 27 into which elastic annulus 28 fits. At this end, the annulus may be slipped into position endwise. In the crimping operation, the dies of FIG. 3 are closed upon areas 22 and 26, as in the case shown in FIG. 4.

Another modification is shown in FIG. 6 wherein ferrule or sleeve 5 has a uniform outside diameter 30 and a recess 31 at each end. The extreme ends 32 may extend over one or both ends of the recesses or they may be omitted. Annuli 33 within the recesses may be held in place by the enclosure so formed. If desired, in this and other forms of the invention, the annuli may be held in place by suitable adhesives. Also, there may be provided a form of sleeve in which only one end thereof has an annulus, and such end may be any one of those illustrated. It is also feasible to have the annulus at an intermediate portion of the sleeve, although this is not the preferred form of the invention.

What is claimed is:

1. In a cable connector having a coaxial cable end, an outer cylindrical sleeve in contact with the outer conductor of said cable end and means coupling said cable end to a cable connector, the improvement which comprises said sleeve having a uniform internal diameter throughout its length, an annular recess within said sleeve at at least one end thereof, an elastomeric annulus in said recess, the inside diameter of said annulus being equal to that of said sleeve, the outer face of said sleeve being compressed to distort said sleeve, said area being angular and having a plurality of faces, said compressed portions being forced tightly against said outer conductor of said cable, the elastomeric annulus being also distorted and conforming to the angular shape of said sleeve, to prevent entrance of moisture past said portions.

2. A cable connector according to claim 1 in which a recess and annulus are at each end of said sleeve.

3. A cable connector according to claim 1 in which said recess is in the inner face of said sleeve, the outer diameter of said sleeve being substantially uniform.

4. A cable connector according to claim 1 in which a recess and annulus are at each end of said sleeve, at least one end of said sleeve embracing the adjacent end of said annulus.

5. A cable connector according to claim 1 in which the distorted areas of said sleeve is hexagonal.

6. A cable connector according to claim 1 in which said sleeve is expanded at said area to provide said recess.

References Cited UNITED STATES PATENTS DARRELL L. CLAY, Primary Examiner.

U.S. C1.X.R. 

